Golf club head

ABSTRACT

An iron type golf club head includes a face member including a face portion and a back surface opposite to the face portion and a main body member which includes a hosel portion and to which the face member is fixed. A plurality of grooves are formed in the back surface. Each of the plurality of grooves includes a first groove portion which is formed on a leading edge side of the face portion in a height direction and extends continuously in a toe-heel direction over an area not less than a half of a width of the back surface in the toe-heel direction.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and the benefit of Japanese PatentApplication No. 2019-116605 filed on Jun. 24, 2019, the entiredisclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an iron type golf club head.

Description of the Related Art

As a method for improving the performance of the face portion of a golfclub head, Japanese Patent Laid-Open No. 2012-071111 discloses a golfclub head in which a portion larger in mass than the surroundings isprovided at a part that becomes the antinode of the vibration of theface portion. Japanese Patent No. 6095348 discloses a golf club head inwhich a plurality of grooves are formed in a part of the back surface ofthe face portion. Japanese Patent Laid-Open No. 10-248970 discloses agolf club head in which the flexural rigidity in the vibration part onthe toe side is increased. Japanese Patent No. 5156994 discloses a golfclub head in which a reinforcing portion is provided at the position ofthe node of the vibration at the time of striking a ball. JapanesePatent Laid-Open No. 11-347161 discloses a golf club head whose naturalfrequency is confined to fall within a specific range.

In general, an iron type golf club head includes a hosel portion on theheel side and a thick sole portion, so that the toe side of the faceportion tends to easily vibrate and the heel side thereof tends tohardly vibrate. Accordingly, the position of the antinode of the naturalvibration of the golf club head tends to be located on the top line sideand on the toe side with respect to the center of the face portion. Ifthe striking point is in the lower portion of the face portion or in thecentral portion in the toe-heel direction, the position of the antinodeand the striking point are separated, so that a carry of a shot may bedecreased.

SUMMARY OF THE INVENTION

It is an object of the present invention to improve the carryperformance upon striking a golf ball at the lower portion of a faceportion.

According to an aspect of the present invention, there is provided aniron type golf club head that includes a face portion and a hoselportion, comprising: a face member including the face portion and a backsurface opposite to the face portion; and a main body member whichincludes the hosel portion and to which the face member is fixed,wherein a plurality of grooves are formed in the back surface, and eachof the plurality of grooves includes a first groove portion which isformed on a leading edge side of the face portion in a height directionand extends continuously in a toe-heel direction over an area not lessthan a half of a width of the back surface in the toe-heel direction.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments (with reference to theattached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front view of a golf club head according to an embodiment;

FIG. 1B is a back view of the golf club head according to theembodiment;

FIG. 2 is a sectional view taken along a line A-A in FIG. 1B;

FIG. 3 is a perspective view of a face member on the back surface side;

FIG. 4 is a view for explaining grooves and ribs;

FIG. 5 is a view for explaining the position of the antinode of thenatural vibration;

FIG. 6A is a view showing another arrangement example of the grooves;

FIG. 6B is a view showing still another arrangement example of the ribs;and

FIG. 6C is a view showing still another arrangement example of thegrooves and ribs.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments will be described in detail with reference tothe attached drawings. Note that the following embodiments are notintended to limit the scope of the claimed invention, and limitation isnot made an invention that requires all combinations of featuresdescribed in the embodiments. Two or more of the multiple featuresdescribed in the embodiments may be combined as appropriate.Furthermore, the same reference numerals are given to the same orsimilar configurations, and redundant description thereof is omitted.

With reference to FIGS. 1A to 2, a golf club head 1 according to anembodiment of the present invention will be described. FIG. 1A is afront view of the golf club head 1, and FIG. 1B is a back view thereof.FIG. 2 is a sectional view taken along a line A-A in FIG. 1B. In thedrawings, an arrow D1 indicates a toe-heel direction, and an arrow D2indicates a height direction of the face portion. The height directionis a vertical direction parallel to the surface of a face portion 4 in astate in which the golf club head 1 is in contact with the ground inaccordance with a predetermined lie angle and a predetermined loftangle.

The golf club head 1 is an iron type golf club head. The presentinvention is applicable to any of a long iron, a middle iron, a shortiron, and a wedge, but is suitable for a long iron and a middle iron interms of carry performance.

The golf club head 1 includes a top line 2 forming the head top portion,a sole portion 3 forming the head bottom portion, the face portion 4,and a hosel portion 5. The hosel portion 5 has a cylindrical shape intowhich a shaft (not shown) is inserted. The lowermost portion of the faceportion 4 forms a leading edge 6.

The face portion 4 forms a golf ball striking surface. In thisembodiment, the face portion 4 forms a flat striking surface, and aplurality of score lines 4 a extending in the D1 direction are formed inthe D2 direction.

Referring mainly to FIG. 2, the golf club head 1 is formed by two parts,a face member 10 and a main body member 20. The face member 10 forms apart of the sole portion 3 and the face portion 4, and the main bodymember 20 forms the remaining part of the golf club head 1 including thehosel portion 5. The periphery portion of the face member 10 is fixed tothe main body member 20 by welding or the like. A space 30 is formedbetween a part of the face member 10 and the main body member 20. Thespace 30 may be filled with an elastic filler material such as a resin.Note that in this embodiment, the golf club head 1 is formed by twoparts, the face member 10 and the main body member 20, but it may beformed by three or more parts.

With reference to FIGS. 2 to 4, the face member 10 will be furtherdescribed. The face member 10 of this embodiment includes a wall portion11 forming the face portion 4 and a wall portion 12 forming the part ofthe sole portion 3, and is a member having an L-shaped verticalsectional shape as a whole. The wall portion 11 has a plate shapeincluding a front surface 11 a and an opposite back surface 11 b, andthe face portion 4 is formed in the front surface 11 a. The back surface11 b has a width Win the D1 direction. As the width (height) in the D2direction, the back surface 11 b has a width H2 on the toe side and awidth H1 (H2>H1) on the heel side.

A plurality of grooves 13 and a plurality of ribs 14 are formed in theback surface 11 b. The grooves 13 and the ribs 14 may be formedintegrally with the face member 10 by casting, or may be formed bymachining such as milling or laser processing. In this embodiments, eachof the number of the plurality of grooves 13 and the number of theplurality of ribs 14 is two. However, the number may be three or more,and the numbers of the grooves 13 and the ribs 14 may be different.

Each groove 13 includes a groove portion 13 a and a groove portion 13 b,and the grooves 13 are spaced apart from each other and extend inparallel. The grooves 13 may be formed to be non-parallel but not tointersect each other. The groove portion 13 a extends continuously alongthe outline of the face portion 4 in the D1 direction over an area equalto or larger than the half of the width W. The groove portion 13 a mayextend continuously in the D1 direction over an area of 60% to 90% (bothinclusive) of the width W. The groove portion 13 b extends along theoutline of the face portion 4 in the D2 direction over an area equal tolarger than the half of the width H1. The groove portion 13 b may extendcontinuously in the D2 direction over an area of 60% to 90% (bothinclusive) of the width H1. In this embodiment, each of the grooveportions 13 a and 13 b is a straight groove, but it may be a curvedgroove.

The groove portion 13 a is formed on the lower side (leading edge 6side) with respect to the central portion in the D2 direction. Thegroove portion 13 a may be formed in an area within a range of (⅓)×thewidth H2 from the lower side in the direction D2, or may be formed in anarea within a range of (¼)×H2 or (⅙)×H2. Assuming that the length of thegroove portion 13 a in the D1 direction is L11, it is expressed byL11>(½)×W. The length L11 may be expressed by L11≤(¾)×W or L11≤(⅘)×W.The groove portion 13 a may be distributed more on the heel side than onthe toe side of the back surface 11 b.

The groove portion 13 b is formed on the heel side with respect to thecentral portion in the D1 direction. The groove portion 13 b may beformed in an area within a range of (⅓)×the width W from the heel sidein the D1 direction, or may be formed in an area within a range of (¼)×Wor (⅙)×W. Assuming that the length of the groove portion 13 b in the D2direction is L12, it is expressed by L12>(½)×the width H1. The lengthL12 may be expressed by L12≤(¾)×H1 or L12≤(⅘)×H1. The groove portion 13b may be distributed more on the lower side than on the upper side ofthe back surface 11 b.

In this embodiment, the heel-side end portion of the groove portion 13 ais connected to the lower end portion of the groove portion 13 b, sothat the groove 13 has an L-shape as a whole when viewed from the backsurface of the wall portion 11. However, the midway portion of thegroove portion 13 a may be connected to the lower end portion of thegroove portion 13 b, the heel-side end portion of the groove portion 13a may be connected to the midway portion of the groove portion 13 b, orthe groove portion 13 a may intersect the groove portion 13 b. Thegroove width of the groove 13 falls within, for example, a range of 0.5mm to 2.0 mm, and the groove depth falls within, for example, a range of0.1 mm to 1.0 mm. The sectional shape of the groove 13 is rectangular inthis embodiment, but may be another shape such as a trapezoid, asemicircle, a semi-ellipse, or a triangle.

Each rib 14 includes a rib portion 14 a and a rib portion 14 b, and theribs 14 are spaced apart from each other and extend in parallel. Theribs 14 may be formed to be non-parallel but not to intersect eachother. The rib portion 14 a extends continuously along the outline ofthe face portion 4 in the D1 direction over an area equal to or largerthan the half of the width W. The rib portion 14 a may extendcontinuously in the D1 direction over an area of 60% to 90% (bothinclusive) of the width W. The rib portion 14 b extends along theoutline of the face portion 4 in the D2 direction over an area equal toor larger than the half of the width H2. The rib portion 14 b may extendcontinuously in the D2 direction over an area of 60% to 90% (bothinclusive) of the width H2. In this embodiment, each of the rib portions14 a and 14 b is a straight protrusion, but it may be a curvedprotrusion.

The rib portion 14 a is formed on the upper side (top line 2 side) withrespect to the central portion in the D2 direction. The rib portion 14 amay be formed in an area within a range of (⅓)×the width H2 from theupper side in the direction D2, or may be formed in an area within arange of (¼)×H2 or (⅙)×H2. Assuming that the width of the extending areaof the rib portion 14 a in the D1 direction is L21, it is expressed byL21>(½)×W. The length L21 may be expressed by L21≤(¾)×W or L21≤(⅘)×W.The rib portion 14 a may be distributed more on the toe side than on theheel side of the back surface 11 b.

The rib portion 14 b is formed on the toe side with respect to thecentral portion in the D1 direction. The rib portion 14 b may be formedin an area within a range of (⅓)×the width W from the toe side in the D1direction, or may be formed in an area within a range of (¼)×W or (⅙)×W.Assuming that the length of the rib portion 14 b in the D2 direction isL22, it is expressed by L22>(½)×the width H2. The length L22 may beexpressed by L22≤(¾)×H2 or L22≤(⅘)×H2. The rib portion 14 b may bedistributed more on the upper side than on the lower side of the backsurface 11 b.

In this embodiment, the toe-side end portion of the rib portion 14 a isconnected to the upper end portion of the rib portion 14 b, so that therib 14 has a vertically and horizontally inverted L-shape as a wholewhen viewed from the back surface of the wall portion 11. However, themidway portion of the rib portion 14 a may be connected to the upper endportion of the rib portion 14 b, the toe-side end portion of the ribportion 14 a may be connected to the midway portion of the rib portion14 b, or the rib portion 14 a may intersect the rib portion 14 b. Therib width of the rib 14 falls within, for example, a range of 0.5 mm to2.0 mm, and the rib height falls within, for example, a range of 0.1 mmto 1.0 mm. The sectional shape of the rib 14 is rectangular in thisembodiment, but may be another shape such as a trapezoid, a semicircle,a semi-ellipse, or a triangle.

With reference to FIG. 5, the position of the antinode of the naturalvibration (primary vibration mode) of the golf club head 1 at the timeof striking a ball will be described. In general, an iron type golf clubhead includes a hosel portion having a rigid structure on the heel side,and the sole width is thicker on the heel side than on the top side.Accordingly, the rigidity is high on the heel side, and low on the toeside and the top line side. Therefore, as shown as a position 15′exemplified in FIG. 5, the position of the antinode of the naturalvibration tends to be located at a position on the toe side and the topline 2 side with respect to the central portion of the face portion 4.When a golf ball is struck at the lower portion or the central portionin the D1 direction of the face portion 4, the striking point isdeviated from the antinode position 15′, so that a carry of a shot maybe decreased.

The iron type golf club head is often used to strike a ball placed onthe ground. Accordingly, it has a high frequency of striking a ball atthe lower portion of the face portion 4. In this embodiment, since theplurality of grooves 13 and the plurality of ribs 14 are provided, it ispossible to make the position of the antinode of the natural vibrationcloser to the lower portion and central portion of the face portion 4,as shown as a position 15. First, since the groove 13 includes thegroove portion 13 a, the rigidity of the face member 10 on the soleportion 3 side can be decreased. Accordingly, the antinode position 15′can be moved to the sole portion 3 side. Similarly, since the rib 14includes the rib portion 14 a, the rigidity of the face member 10 on thetop line 2 side can be increased. Accordingly, the antinode position 15′can be further moved to the sole portion 3 side. As a result, when agolf ball is struck at the lower portion of the face portion 4, thestriking point is closer to the antinode position 15, so that anincrease in a carry of a shot can be achieved.

In addition, since the groove 13 includes the groove portion 13 b, therigidity of the face member 10 on the heel side can be decreased.Accordingly, the antinode position 15′ can be moved to the heel side.Similarly, since the rib 14 includes the rib portion 14 b, the rigidityof the face member 10 on the toe side can be increased. Accordingly, theantinode position 15′ can be further moved to the heel side. As aresult, when a golf ball is struck at the central portion of the faceportion 4, the striking point is closer to the antinode position 15, sothat an increase in a carry of a shot can be achieved.

In this manner, in this embodiment, the position of the antinode of thenatural vibration of the golf club head 1 at the time of striking a ballcan be moved closer to the central portion and lower portion of the faceportion 4, as shown as the position 15. In this case, when a ball isstruck at the lower portion of the face portion 4, which is a frequentstriking point, or at the central portion of the face portion 4, whichis a striking point upon which a golfer can make a nice shot, thestriking point is close to the position 15 of the antinode of thenatural vibration, so that a larger carry of a shot can be obtained andthe carry performance can be improved.

Other Embodiments

Both the plurality of grooves 13 and the plurality of ribs 14 are usedin the embodiment described above, but it is possible to move theposition of the antinode of the natural vibration closer to the centralportion of the face portion 4 by using either of the plurality ofgrooves 13 and the plurality or ribs 14. In addition, the groove 13 mayinclude the groove portion 13 a alone, and even in this case, it ispossible to move the position of the antinode of the natural vibrationcloser to the central portion of the face portion 4 in the D2 direction.Similarly, the rib 14 may include the rib portion 14 a alone, and evenin this case, it is possible to move the position of the antinode of thenatural vibration closer to the central portion of the face portion 4 inthe D2 direction. FIGS. 6A and 6B show examples of these cases. In theexample shown in FIG. 6A, there is no rib 14, and each of the pluralityof grooves 13 includes the groove portion 13 a alone according to theembodiment described above. In the example shown in FIG. 6B, there is nogroove 13, and each of the plurality of ribs 14 includes the rib portion14 a alone according to the embodiment described above.

In addition, as another example of the plurality of grooves 13, thegroove 13 including the groove portion 13 b and the groove 13 includingno groove portion 13 b may be mixed. Similarly, as another example ofthe plurality of ribs 14, the rib 14 including the rib portion 14 b andthe rib 14 including no rib portion 14 b may be mixed. FIG. 6C shows anexample of this case. In the example shown in FIG. 6C, three grooves 13are formed, and one groove 13 among them includes the groove portions 13a and 13 b but each of the remaining two grooves 13 includes the grooveportion 13 a alone according to the embodiment described above. Further,in the example shown in FIG. 6C, three ribs 14 are formed, and one rib14 among them includes the rib portions 14 a and 14 b but each of theremaining two ribs 14 includes the rib portion 14 a alone according tothe embodiment described above. In the arrangement example shown in FIG.6C, the position of the antinode of the natural vibration can be movedmore in the direction D2 while less in the D1 direction as compared withthe example shown in FIG. 4.

The invention is not limited to the foregoing embodiments, and variousvariations/changes are possible within the spirit of the invention.

What is claimed is:
 1. An iron type golf club head that includes a faceportion and a hosel portion, comprising: a face member including theface portion and a back surface opposite to the face portion; and a mainbody member which includes the hosel portion and to which the facemember is fixed, wherein a plurality of grooves are formed in the backsurface, and each of the plurality of grooves includes a first grooveportion which is formed on a leading edge side of the face portion in aheight direction and extends continuously in a toe-heel direction overan area not less than a half of a width of the back surface in thetoe-heel direction.
 2. The golf club head according to claim 1, whereineach of the plurality of grooves includes a second groove portion whichextends from a heel-side end portion of the first groove portion to atop line side, and each of the first groove portion and the secondgroove portion extends along an outline of the face portion.
 3. The golfclub head according to claim 1, wherein a plurality of ribs are formedin the back surface, and each of the plurality of ribs includes a firstrib portion formed on the top line side of the face portion in theheight direction.
 4. The golf club head according to claim 3, whereinthe first rib portion extends continuously in the toe-heel directionover an area not less than the half of the width of the back surface inthe toe-heel direction.
 5. The golf club head according to claim 4,wherein each of the plurality of ribs includes a second rib portionwhich extends from a toe-side end portion of the first rib portion tothe leading edge side, and each of the first rib portion and the secondrib portion extends along the outline of the face portion.
 6. The golfclub head according to claim 2, wherein the second groove portionextends over an area not less than a half of a heel-side width of theback surface in the height direction.
 7. The golf club head according toclaim 5, wherein the second rib portion extends over an area not lessthan a half of a toe-side width of the back surface in the heightdirection.
 8. The golf club head according to claim 3, wherein theplurality of grooves are spaced apart from each other, and the pluralityof ribs are spaced apart from each other.
 9. The golf club headaccording to claim 3, wherein the plurality of grooves are two groovesparallel to each other, and the plurality of ribs are two ribs parallelto each other.
 10. An iron type golf club head that includes a faceportion and a hosel portion, comprising: a face member including theface portion and a back surface opposite to the face portion; and a mainbody member which includes the hosel portion and to which the facemember is fixed, wherein a plurality of ribs are formed in the backsurface, and each of the plurality of ribs includes a first rib portionwhich is formed on a top line side in a height direction of the faceportion and extends continuously in a toe-heel direction over an areanot less than a half of a width of the back surface in the toe-heeldirection.